1. Field of the Invention
The present invention relates to a cleaning robot and a method for controlling the same. More particularly, the present invention relates to a cleaning robot which easily discriminates or (discerns) between a signal reflected from an obstacle and a direct noise, and a method for controlling the same.
2. Description of the Conventional Art
A cleaning robot is a kind of mobile robot which absorbs dust and foreign material while moving by itself in a certain space such as a house or an office.
The aforementioned cleaning robot includes a traveling means including right and left wheel motors for moving the cleaning robot, a detection sensor for detecting and avoiding a variety of obstacles within a cleaning area, and a control means for controlling the traveling means and the detection sensor to perform cleaning, as well as the components of a general vacuum cleaner which absorbs dust and foreign material.
FIG. 17 is a schematic view of an ultrasonic sensor of a cleaning robot according to the conventional art. FIG. 18 is a graph illustrating signals obtained by the ultrasonic sensor of FIG. 17.
As illustrated in FIGS. 17 and 18, the cleaning robot according to the conventional art includes a case 1 and an ultrasonic sensor installed on the surface of the case 1. The ultrasonic sensor includes a transmitter portion 2 and receiver portion 3.
The transmitter portion 2 and the receiver portion 3 are installed spaced by a predetermined distance from each other, and recognizes obstacles 5 and 6 by receiving an ultrasonic wave transmitted from the transmitter portion 2.
If the transmitter portion 2 transmits a predetermined ultrasonic wave, this generates a direct noise 7 flowing along the case 1, as well as the ultrasonic wave transmitted to the outside of the case 1.
However, as illustrated in FIG. 18, there is a problem that the receiver portion 3 is unable to discriminate (or discern) between the direct noise 7 and an obstacle signal 8 that are received at a similar time because the receiver portion 3 receives the direct noise 7 transmitted along the surface of the case 1 and the signal 8 reflected from the spaced obstacle 5.
Therefore, the cleaning robot according to the conventional art has the problem of not being able to recognize the obstacle 5 as far as the position spaced by a predetermined distance from the case 1 due to the direct noise 7.